ECU confusion

so i've got a 94 accord ex with a full 99 h22a swap in it. i picked the car up in the condition that it's in, so i'll lay it out:

i also have a 96 accord ex, stock. the wires in the right fender fell out during an accident involving the wheel well "disappearing" lol. the ecu fried. it took a while to get the right new one, and in the process learned how ecus really work. the 5th time it was the right one, but throughout the trials, with the wrong computers, the rev limiter was wrong, no vtec activation, etc. so, back to the 94:

the kid put a p13 computer out of a 95 lude in it, so there's a problem there. it hits vtec at 4500, limits at 4900. sucks. so i know i need to do a bit of work. i have narrowed the computer the i need down to the p5p series. there are two that will work. the P5P-L03 and the P5P-L04. what the hell is the difference between them?? i dont get it. the specs appear to be exactly the same.

also, a question i have is about the harnesses that i need. will the ones that are hooked up to the P13 work? and how would i put in a DLC?